In ASP.NET development, F# also offers productivity advantages over VB and C#. F# is different because it is statically checked and type-safe. It addresses weaknesses in ASP.NET development like untyped values, complex form construction, and using strings for IDs and method names that connect markup with code-behind (class-files). Writing a web application in F# on the WebSharper platform can be less-time consuming if a developer is not great at writing web apps in JavaScript. Through WebSharper, developers can write a web app using a large subset of F# and .NET core libraries and then just let WebSharper map the code to JavaScript. WebSharper can integrate with ASP.NET applications, but it is different from the standard approach because it builds applications from miniature web pages called "pagelets". The pagelets correspond to functions on the client-side and they are automatically translated into JavaScript. WebSharper supports a wide range of JavaScript libraries, making it easy for developers to optimize their code in whatever way they choose. jQuery, qooxdoo, Flapjax, and Yahoo UI are all supported by WebSharper. The leap from F# to JavaScript is manageable because both are functional languages that support lambda expressions and closures. Another unique part of WebSharper is a "formlet". A formlet is a special pagelet that provides form functionality. Formlets in Web Sharper run and validate on the client, submitting their result to a either a client- or a server-side callback.
